College of Resource and Environmental Sciences, Xinjiang University, Urumqi, 830046, People's Republic of China.
Xinjiang Common University Key Laboratory of Smart City and Environmental Stimulation, Xinjiang University, Urumqi, 830046, People's Republic of China.
Environ Sci Pollut Res Int. 2020 May;27(13):15057-15067. doi: 10.1007/s11356-020-07701-y. Epub 2020 Feb 17.
The water-sediment interface of lakes is an important and unique area of the water environment; the geochemical behavior of nutrients in this area has a significant impact on the quality of the water environment and ecosystems, especially in shallow lakes. However, most studies do not provide direct in situ evidence for this in shallow lakes in arid regions; in order to explore the coupling relationship between phosphorus (P) and iron (Fe) in a sediment profile, we conducted a high-resolution analysis of liable Fe and P in sediments taken from the Chaiwopu Lake using ZrO-Chelex thin film diffusion gradient technology (ZrO-Chelex DGT). The results show that (1) the vertical spatial distribution trend of the liable P and Fe in the sediments from each sampling site is essentially similar. The contents of the liable P and Fe ranged from 0.004-0.125 mg/L and 0.050-0.190 mg/L, respectively, and the synchronous distribution of the micro-interface concentration reflects the coupling relationship between them. (2) The correlation analysis of the liable P and Fe concentrations showed that there were significant linear correlations between them (P < 0.05, bilateral). (3) The diffusion fluxes of P and Fe were - 51.7665.12 μg (m d) and - 451.27457.06 μg (m d), respectively, and were shown to be negative at the sediment-water interface for most of the samples, which showed that P and Fe were released from the overlying water into the sediments. (4) This research showed that the diffusive fluxes at the different sites are quite different, which indicates that the phosphorus and iron pollution in the sediments of the Chaiwopu Lake is affected by exogenous inputs. There was no significant correlation between P release flux and pH, ORP, conductivity (EC), the TDS of the overlying water, or the pH, salinity (Ca, Mg), and nutrient (organic matter) content of the sediment. The release flux of Fe is affected by the pH of the sediment. The results of this study provide references for the research of elements in the water-sediment interface of shallow lakes in arid regions, as well as other areas.
湖泊水-沉积物界面是水环境中一个重要而独特的区域；该区域中营养物质的地球化学行为对水环境和生态系统质量有重大影响，特别是在浅水湖泊中。然而，在干旱地区的浅水湖泊中，大多数研究并未提供这方面的直接现场证据；为了探究沉积物剖面中磷（P）和铁（Fe）的耦合关系，我们采用ZrO-Chelex 薄膜扩散梯度技术（ZrO-Chelex DGT），对柴窝堡湖沉积物中的易溶性 Fe 和 P 进行了高分辨率分析。结果表明：（1）各采样点沉积物中易溶性 P 和 Fe 的垂直空间分布趋势基本相似。易溶性 P 和 Fe 的含量分别为 0.004-0.125mg/L 和 0.050-0.190mg/L，微界面浓度的同步分布反映了它们之间的耦合关系。（2）易溶性 P 和 Fe 浓度的相关分析表明，两者之间存在显著的线性关系（P<0.05，双侧）。（3）P 和 Fe 的扩散通量分别为-51.7665.12μg/（m·d）和-451.27457.06μg/（m·d），大多数样品在沉积物-水界面表现为负值，表明 P 和 Fe 从上覆水向沉积物释放。（4）本研究表明不同站位的扩散通量差异较大，表明柴窝堡湖沉积物中磷和铁污染受到外源输入的影响。P 释放通量与上覆水的 pH、氧化还原电位（ORP）、电导率（EC）、总溶解固体（TDS）或沉积物的 pH、盐度（Ca、Mg）和养分（有机物）含量均无显著相关性。Fe 的释放通量受沉积物 pH 的影响。本研究结果为干旱地区浅水湖泊水-沉积物界面元素研究以及其他地区提供了参考。
